It is, of course, generally known to store and/or transport chemicals having hazardous characteristics via pressurized containers. Further, it is also generally known to clean these containers using a variety of methods and systems. In the past, cleaning pressurized containers entailed venting excess gaseous material to the atmosphere. Further, unpressurized containers contained bottom hatches or valves for draining liquid chemicals. However, many hazardous chemicals escaped into the environment thereby causing health risks for humans, vegetation and wildlife. With the advent of environmental standards and compliance, however, venting or draining hazardous chemicals to the environment has generally become illegal.
Moreover, some chemicals that may be stored within pressurized containers may be highly reactive in the presence of water and may form acids that may be damaging to equipment as well as the environment. Although a flare may be useful to dispose of chemicals that are flammable, some chemicals do not incinerate easily or may form extremely hazardous substances upon incineration. Typically, scrubbers or sparge tanks are necessary to dispose of these chemicals or byproducts of these chemicals.
While some of the gases contained within the containers may be relatively easy to recover and dispose of by venting the pressurized containers to a flare or to a sparge tank, it is difficult to remove all of the gases contained therein. Further, liquid product may remain inside a container after cleaning. Typical systems and methods of cleaning pressurized containers may involve injecting the container with a quantity of steam that may aid in bringing the liquid chemicals to the gaseous phase and removing the steam/gaseous chemical product combination for incineration or disposal. However, problems may occur using steam to remove chemicals from pressurized containers since steam may condense within the container forming liquid water or ice. The liquid water or ice may mask the presence of the chemicals from detectors or otherwise encapsulate the chemicals. Further, the liquid water or ice may interfere with the removal of the chemicals from the container. Moreover, liquid water or steam may react with certain chemicals, such as for example, chlorine gas or sulfur dioxide gas to form hazardous byproducts, such as acids, that may damage equipment or the environment if released. For example, chlorine gas and sulfur dioxide gas may react with water according to the following reaction:                1. Cl2+H2O→HCl+HOCl        2. 2SO2+2H2O+O2→2H2SO4         
In addition, steam or liquid water may be difficult to remove from the container since water droplets may stick to the inside surfaces of the container, piping and/or equipment. A further step would be required for drying the container and/or the equipment, thereby requiring additional time, equipment and expense.
Another method of removal may include entering the container to manually remove the chemical and/or any other debris, such as, for example, scaling, that may be contained within the container. While this may be a relatively thorough way to remove the chemical from the container, it may be very dangerous, as it requires an individual to actually enter the container thereby exposing the individual to any chemicals that may be contained therein. Further, by opening the container, there may be a significant risk that some of the chemicals may escape into the environment.
Therefore, an improved method for cleaning pressurized containers is necessary. Particularly, a system is needed that overcomes the problems associated with typical cleaning systems. Further, a system is needed that cleanly and efficiently removes chemicals from a pressurized container and transports the waste product to a proper disposal system such as a flare or a reaction tank to incinerate or otherwise safely dispose of the chemicals.